期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2004
卷号：101
期号：10
页码：3650-3655
DOI：10.1073/pnas.0306587101
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Tissue plasminogen activator (tPA) is a serine protease that catalyzes the conversion of plasminogen (plg) to plasmin, which in turn functions to degrade extracellular matrix proteins in the central nervous system. The tPA-plasmin system plays a role in synaptic plasticity and remodeling. Here we show that this protease system participates in the rewarding effects of morphine by acutely regulating morphine-induced dopamine release in the nucleus accumbens (NAcc). A single morphine treatment induced tPA mRNA and protein expression in a naloxone-sensitive manner, which was associated with an increase in the enzyme activity in the NAcc. The acute effect of morphine in inducing tPA expression was diminished after repeated administration. Morphine-induced conditioned place preference and hyperlocomotion were significantly reduced in tPA-/- and plg-/- mice, being accompanied by a loss of morphine-induced dopamine release in the NAcc. The defect of morphine-induced dopamine release and hyperlocomotion in tPA-/- mice was reversed by microinjections of either exogenous tPA or plasmin into the NAcc. Our findings demonstrate a previously undescribed function of the tPA-plasmin system in regulating dopamine release, which is involved in the rewarding effects of morphine.
